Fortunately found this thread here

Had finished the whole series and now rewatching it
Seriously cant get higurashi out of my head ever since i watched it

The whole mystery just happen in such a way that make ppl feel so creepy yet so sad about the actors behaviour which make them commit killing to their friend just because of misunderstand or suspicion
It is not some type of horror movie that make ppl keep thinking bout it, its not like those horror movie that keep haunting u by the scariness of the actor and story,
but at first it show u their happy life with friends and in a nice living place, but due to some event they start to act abnormally and most of them lost their sanity
On the way watching it i feel like i can feel their sadness in their heart like when keichi distrust his friend at the first arc, he does not wan to abandon his friend but his suspicious tell him to stay away from them like they really going to kill him.
When think of his feeling on his perspective, can understand how hard was it to make such decision

Although had done watching but something haunt me...
in the end there's no solid proof saying that the characters act abnormally is entire due to the parasite isn't it?
The hinamizawa syndrome is just hypthesis created by that profesor and research inherit by miyo, although the whole acting using that as a reason to explain they abnormal act